Friction draft gear



m. Railway Dran nppuancas earcn oom A. F. STUEBING FRICTION DRAFT GEAR Nov. l2, 1935.

Filed Jan. 24, 1931 2 sheets-sneet 2 their normal positions a Patented Nov. 1K2,

UN1TED STATES PATENT ol-Fica Y' z,czo,4e1 v l mbesnllflbm. New rm, N. Ir. appuesnongmnry 2'4, 1931, serialfNo. 511,023'

.somma (ciels-sz) i My invention relates to friction draft gearsfor railway cars and it'has for its principal object the yprovision of` improved means for facilitating the return of the friction elements thereof to A primary feature of fter operation of the gear; the invention consists in providing a draft gear'with a plurality of friction elements, one of which is providedv with curved and plane surfaces in frictional engagement with the load sustaining member of the Seal'.

Another feature of the invention consists in providing a draft gear having a load sustaining column member with a plurality of .friction elements one of which is provided witha curvd surface in frictional engagement'withthe column is provided with surfaces also/in friccolumn member.

invention consists in member and another f which angularly disposed planetional engagement with the A further feature of the providing a draft gear having a load sustaining column member with a plurality of friction elements one of which is provided with two. plane by a curved surface respectively in frictional engageme' t with the column member.

A still further feature of the invention consists in providing a draft gear having a load sustaining column member with a elements one of plurality of friction which is providedwith a curved friction surface and another one of whiclr'is provided with substanuany normal plane friction surfaces connected by a curved friction surface.

Other and more specific features Of the invention 'residing' in advantageous forms,` combinaparts will hereinafter apdrawings illustrating a preferred emin .section and partly view of the gear.A

view partly in section and partly line 3^3of Figure 2.

Figures 4 and 5 are vertical-sectional views taken on lines 4--4 and 5-5 of Figure l.

Figure 6 is an enlarged inside side elevational view of one of the friction elements 'of the gear.

Figure 7 is an end elevational view of the friction element of Figure 6 as seen from hand side of that` figure.

the right Figure 8 is an enlarged inside side elevational view ofianother of the friction elements. Figure 9 is an end elevationalview of the friction element of Figure 8 as seen from hand side of that figure.

the right' opposed inner and outer friction surfaces of each of shoes 8 and .umn member is preferably in the form of a hous- 5.

ing and is provided with a hollow body portion 3 closed at its inner end by a wall^ 4. If desired the housing may be convenientlyv formed adjacent its inner end with laterally projecting portions 5 adapted to cooperate wtih suitable stops y10 (not shown) to prevent inward movement of the housing with respect to the car. These portions may be conveniently rigidified with a plurality of reinforcing ribs 6.

The frictiony elements of the gear are disposed within the forward portion of the housing and comprise a central wedge member 1 and a plurality of shoes, preferably three in numbe','des ignated by the reference numerals 8, 9 and I0. The central wedge member, is formed with three similarly formed y angularly disposed wedging surfaces II for respectively cooperating with the three shoes. v

The shoes designated by the reference numerals 8 and 8 are identical and each is formeizwitl 25 an I3, respectively. The inner friction surface I2 of each of these shoes` is adapted to be disposed in a-plane substantially parallel with the adiacent surface II of the wedge member for cooperating therewith. 'Ihe outer friction surface I3 9 is cylindricaliy curved and is adapted to cooperate with similarly formed friction'surfaces I4 on the-.interior of the for- .ward portion of the body portion 3 of the hous- 35 ing. The friction shoes may advantageously be formed of cast metal and provided with plate-like portions I5 and I8' on the outer sides of which the surfaces I2 and I3 are respectively formed. Adjacent their outer ends the plate-like portions 40 intersect and continue as an outwardly extending lip or lug I1 normally disposed in spaced overlapping relation with a cylindrical portion I8 of the wedge. The plate-like portions are connected by side walls Iiland an intermediate web or flange 20 and, for a purpose to be hereinafter/ described, the inner end of the plate portions are respectively formed with inwardly projecting flanges 2| 'and 22. g

The other shoe I0 is formed on its inner side 50 with a wedging surface 23 eooperable with the adjacent surface of the wedge member while on Il are plane surfaces and are preferably disposed tiallynormal to each other while surface Il which connects 24 and 25 is cylindrically curved, the axis of curvature thereof being. less than the axis of curvature of surfaces il of shoes To prevent the forces transmitted from the housing'to the shoe from concentrating in the portions of the housing immediately .adjacent the side edgesof the shoes, surfaces 2l and 2l may advantageously be curved as indicated at K Il. and Il* 'respectively'. 'Ihe interior of the y forward end of the housing is4 formed with plane and curved portions for respectively cooperating with the correspondingly formed surfaces of the exterior of shoe Il. Since shoe I. is of the same construction as shoes l and 9, with the exceptions of the contour `of its outer surface, corresponding parte of the shoes are designated by similar reference numerals. e Disposed within the housing are a plurality for returning the friction ae positions illustrateil in Figures l esearhasbeenoperatedineither The spring 21 cooperates with the l of the housing and the iiangesrfl'of ethesnrlnsllenmesthenanges. lof shoes'and any suitable portion of the wall such as an inwardly projecting boss. friction elements are preferably retained in bled position by a longitudinally extending Qlononeendofwhichisaheadll which be conveniently disposed within the boss 28 on the other end of which is a removable I2 disposed within a recess 33 in the cylindriportion il of the wcdse. In the operation of the gear the vcentral wedge y per converge inwardly thereby causgm movement of the shoes relative to the cenof the surfaces. 'Ihus the `forces opposing lateral movement of shoes I and are disposed' at angles to the force applied by the wedge to the shoes and the former are, therefore, greater than the latter. Upon referring to shoe i0, it will be observed that the force set up in` the housing opposing the lateral forces exerted by the wedge on the shoe lact normal to the plane friction surfaces 2l and 26 and radial to the, curved surface 22. Thus the forces opposing lateral movement of shoe Il are also disposed at anglesfto the forces applied by the wedge to the moe and the former are greater than the latter. (However, due to' the fact that shoe il has a greater number of transverse increments of surface on its outer face forming a greater angle to the force transmitted thereto by the wedge than l5 shoes l and l have with respect to the forces transmitted to them by the wedge, the summation of the forces set up in the housing opposing lateral movement of shoe I0 are'of greater magnitude than the summation of the forces set/20 up in the housing opposing lateral movement of shoes 0 and 0. Shoe i0, therefore, hasa greaterfrictional resistance to movement than l and l. 'Ihis difference in frictional resistance will have comparatively little effect during clo- 86 Vsure `oi the gear except to produce a tendency for shoes I and `lvto'triivel a greater distance than shoe Il, thereby causing the spring to exert a greater force on each of shoes I and i than 'on-'shoe Il, but when the compressive force ap'- I0 plied tothe gr is removed, shoes l and i. since they have less frictlonal resistance to movement than shoe il, will tend to release in advance of slioe il; thereby releasing the pressure between wedge il and shoe Il and enecting quick release 8l of the gear.

The structure disclosed in this application produces ;a combination of several desirable conditions. 'Ihe contours of the friction elements are substantially tangent to the sainel circle at 4o their adjacent edges, thereby minimizing bending stresses in the housing. 'Ihe shoehaving the plane surfaces is so formed that the plane surfaces lie without the circle passing through the outer edges of the`sidesof the three shoes which i5 lie adjacent to each other, so that the diameter, and therefore the capacity, of the spring arenot reduced by the .use of the plane surfaces. Purthermore the wedge Il exerts equal forces on the three shoes). l and il and the frictional area ,M ofshoe Ilyarles butlittlefromtheareaofshoes l and l. It is to be noted that the plane frictior'isurfaces o shoe Il prevent the shoes from rotating about the axis of the gear, the tendency toward rotation being caused by movement of the coil springs in closing and releasevof the gear. However. the shoes l and I may rotate slightly due to the clearance between them and the shoe Il -so as to compensate for deviation from paroi-0 lelism of their plane wcdging faces. y Prom the foregoing it will be appreciated that the construction of the gear is such that the returnof the friction elements to normalposition after closure of the gear is'greatly feelg- ,4

I claim: f A 1. A 'draft gear for l'ililrrl'l oars involving a .load sustaining column member: wedging means; and a plurality of friction elements respectively 70 havingfacesinclinedinthesamedirectionwith repecttothelongitudinalaxisofthegearfor cooperating with said wedgingmeans, said friction elements being movable relatively to said column member and beingurespectively provided column member and the element having only with friction surfaces in engagement with the latter, and forming equal angles with the wedging faces, one of said elements having plane frictim surfaces and the other of seid elements naving cylindrical friction surfaces, said surfaces being .so arranged that the summation of the friction producing forces between the column member and the element having the plane sur- ;faces is greater than the summation of the friction producing forces between the column member and the other of said elements.

2. A draft gear for railway cars involving a load sustaining column member; a plurality of friction elements cooperable therewith and movable relativelythereto; means for moving the shoes longitudinally and exerting equal lateral forces thereon; and spring lmeans opposing movement of said elements, one of said elements having a curved friction surface and another of said elements having plane and curved friction surfaces, each of said friction surfaces being in engagementwith the column member, the summation of the friction producing forces be# v tween the column member and the element vhaving the plane and curved surfaces heilig greater than the summation' of the friction iproducing forces between the column member and the element having only the curved surface.

3. A draft gear for railway cars involving a housing having friction surfaces; a central wedge member, disposed within the housing, and having wedging faces inclined in the same direction along the longitudinal axis of the gear; a plurality of/y movable friction elements operatively interposed between the wedge andhousing, having races in engagement with said wedging :ages of the wedge member and forming equalangles 1 with theY friction surfaces of the housing;` and spring means opposing movement of said ele-- ments, one o`f said elementsw having plane and cylindrical friction surfaces, and the other of saidV elements having only cylindrical friction each of said surfaces being in frictional engagement with thiihiousing,V the summationof the friction producing forces homingandtbeelementhavingtheplaneandcylincylindrical friction surfaces.

4. A draft gear for railway cars involving a housing; a central wedge memberdisposed within the housing and having wedging faces in 5 clined in the same direction along the longitudinal axis of the gear; a plurality of movable friction elements operatively interposed between the wedge and housing and having faces in engagement with said wedging faces of the wedge member; and spring means opposing movement of said elements, one of said elements having two plane surfaces connected by a curved surface, and the other of said elements having two cylindrical surfaces, each of l.said surfaces being in l5 `1 frictional engagement with the housing.

5. A draft gear for railway cars involving a load sustaining column member, a plurality of friction elements movable Vrelatively to the column member; wedging means having faces, inclined in the same direction along the axis of the gear and exerting substantially equal forces on all o f said friction elements; and spring means opposing movement of said elements, at least one of said elements having a curved friction surface and another f said elements having two substantially plane friction surfaces ,connected by a curved friction surface, each of said friction surfaces being in engagement with the column member.

6. A draft gear for railwavcars involving a load-sustaining column member; friction elements, a pluralitrot' said elements being provided with substantially coaxial cylindrical friction surfaces; and another element having plane friction surfaces; a wedging element :having wedging faces extending in thel same direction along the axis of the gear and exerting substantially equal forces on all said friction elements;` and spring means opposing movement of said elements; the summation of the friction-producing forcesbetwemthecolumnmemberandthefriction elements having the cylindrical friction surfaces bdng ,greater than between the .column the friction .elements having the 

